#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>

struct sigaction act, oact;
void handler(int signo)
{
	printf("get a signal:%d\n", signo);
	sigaction(2, &oact, NULL);
}
int main()
{
	memset(&act, 0, sizeof(act));
	memset(&oact, 0, sizeof(oact));

	act.sa_handler = handler;
	act.sa_flags = 0;
	sigemptyset(&act.sa_mask);

	sigaction(2, &act, &oact);
	while (1){
		printf("I am a process...\n");
		sleep(1);
	}
	return 0;
}
